Kubernetes for Java Developers

Kubernetes for Java Developers

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  © 2017 SoftwareAG. All rights reserved. For internal use only Anthony Dahanne. Montreal JUG, May 2nd, 2018 KUBERNETES FOR JAVA DEVELOPERS
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  LET ME INTRODUCEMYSELF „Anthony Dahanne, Software Engineer @ Terracotta, a Software AG company „Working on the Management and Monitoring in Terracotta products (Ehcache, Terracotta Store) „Also working on Terracotta products integration with cloud (Docker, Kubernetes, AWS, etc.) Go and try our latest images and instructions at : https://store.docker.com/publishers/softwareag https://github.com/SoftwareAG/terracotta-db-cloud All this presentation’s examples are on Github: https://github.com/anthonydahanne/kubernetes-for-java-developers
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  AGENDA Docker & Javarefresher in 2 slides Kubernetes concepts and examples Tools to become a productive developer with Kubernetes Coding Java applications leveraging Kubernetes
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  CONTAINERS IN 1SLIDE • Containers all use host OS kernel • Host OS can be running in a VM or barebone • Host OS Linux distribution does not matter • - only the kernel does ! • Isolation performed with namespaces and cgroups • namespaces : limits what you can see • pid, net, mnt, uts, ipc, user • cgroups : limits what you can use • memory, CPU, block IO, network (with iptables) THAT’S JUST AN ISOLATED PROCESS ! https://www.enterprisetech.com/2014/08/18/ibm-techies-pit-docker-kvm-bare-metal/ https://www.slideshare.net/jpetazzo/anatomy-of-a-container-namespaces-cgroups-some-filesystem-magic-linuxcon
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  JAVA AND LINUXCONTAINERS • The JVM “guesses” available CPU and Memory resources available on the host • Although it can be set manually • -XX:ParallelGCThreads, • -XX:CICompilerCount • -Xmx • Since Java SE 8u131, the JVM • is “Docker aware with respect to Docker CPU limits transparently” • has new options for detecting memory limits (not transparent, yet) • -XX:+UnlockExperimentalVMOptions • -XX:+UseCGroupMemoryLimitForHeap BEWARE WHAT THE JVM CAN SEE ! (AND USE !) Demo : Memory Eater
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  KUBERNETES A CONTAINER ORCHESTRATOR
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  KUBERNETES INTRODUCTION • Initialrelease June 7th 2014 • Apache 2 License, written in Go • heavily inspired by Borg, internal system from Google • Currently 1.10 (a new release every 3 months on average) • Under the umbrella of the Cloud Native Computing Foundation • that includes Oracle, Intel, IBM, Pivotal, Redhat, etc. • along with Prometheus, OpenTracing, containerd, CNI, FluentD, etc. FROM BORG TO CNCF https://github.com/cncf/landscape
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  KUBERNETES LOCAL COMMUNITY •Kubernetes / CNCF Montreal Meetup every quarter • Almost 1000 members • Slack channel sync’ing all other Canadians K8s communities k8scanada.slack.com • Led by Archy, CNCF Ambassador YOU ARE NOT ALONE !
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  KUBERNETES ARCHITECTURE MASTER NODES,WORKER NODES, SOME NETWORKING… By Khtan66 - CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=53571935
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  Deployment (Declarative Updates) >kubectl set image deployment/tmc-deployment tmc=tmc:10.3 > kubectl rollout status deployment/tmc-deployment Replica Set (Match and Scale definitions) spec: replicas: 3 selector: matchLabels: tier: tmc KUBERNETES WORKLOADS (PODS AND CONTROLLERS) DEPLOYMENT > REPLICA SET > POD > CONTAINER Pod spec: containers: - name: tmc image: store/softwareag/tmc:10.2 command: [‘start.sh’] - name: helper-container image: busybox command: ['sh', '-c', 'sleep 3600’] volumes: (secrets, configmaps, etc.) hostname: terracotta + Jobs, StatefulSets, Daemon sets, etc. metadata: labels: tier: tmc
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  KUBERNETES SERVICES • ClusterIP(default) • Exposes the service on a cluster- internal IP • NodePort • Exposes the service on each node’s IP address, on a defined port • LoadBalancer • Exposes the service externally, using the cluster provided load balancer • no default LoadBalancer on premise … HOW DO YOU EXPOSE YOUR WORKLOADS “A Kubernetes Service is an abstraction which defines a logical set of Pods and a policy by which to access them” https://kubernetes.io/docs/concepts/services-networking/service/ Node A Pod-1 labels tier:frontend Service spec: type: LoadBalancer ports: -port:80 selector: tier:frontend in | outside NodeB Pod-2 labels tier:frontend
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  KUBERNETES VOLUMES, CONFIGMAPS AND SECRETS • ConfigMaps and Secrets are stored on the etcd key/value store • Often times, volumes are abstracted away with PersistentVolumes and PersistentVolumeClaims • Many types of volumes are available : hostPath, nfs, cloud specific, etc. YOU CAN MOUNT THEM ALL ! Pod apiVersion: v1 kind: Pod spec: containers: - name: terracotta-server image: store/softwareag/terracotta-server:10.2 volumeMounts: - name: config-volume mountPath: /config - name: data mountPath: /data volumes: - name: config-volume configMap: name: tc-config - name: data hostPath: path: /usr ConfigMap apiVersion: v1 kind: ConfigMap metadata: name: tc-config data: tc-config.xml: | <xml></xml>
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  KUBERNETES DEPLOYMENTS • Cloudproviders • Google Cloud with GKE • Microsoft Azure with AKS • Amazon with Kops (although EKS is around the corner) • Playgrounds : Katacoda and Play with Kubernetes • On-premise • Hard way • Kubeadm • Local • Minikube • Minishift • Docker for Mac (more on this one later) CLOUD, ON-PREMISE, LOCAL Demo : Fullstack app deployment
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  BEING A PRODUCTIVEDEVELOPER WITH KUBERNETES TOOLING !
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  • IDE plugins •auto completion for Dockerfile • To build and deploy images from the IDE • Build tooling Docker integration (Maven / Gradle) • To build Docker (and push) images during the build • Maven Docker plugin DOCKER TOOLING • Docker for Mac / Win 10 • As of today, only the edge version comes with Kubernetes support
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  KUBERNETES OWN TOOLING •IDE plugins • auto completion for Dockerfile • To build and deploy images from the IDE • Build tooling Docker integration (Maven / Gradle) • To build Docker (and push) images during the build • Kubectl (obviously !) • and its bash / zsh auto completion ! • Kubernetic UI • and more !
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  KUBERNETES TOOLING :HELM • Helm is installed on the client, Tiller is the server side • With Helm you deploy / create Charts that are run as Releases • In a Chart, you package your Kubernetes manifests, and your dependencies • A very notable feature is the “templatization“ of your Kubernetes manifests APT / YUM FOR KUBERNETES apiVersion: apps/v1beta2 kind: Deployment spec: replicas: {{ .Values.replicaCount }} selector: matchLabels: app: {{ template "terracotta-server.name" . }} release: {{ .Release.Name }} template: metadata: labels: app: {{ template "terracotta-server.name" . }} release: {{ .Release.Name }} spec: hostname: {{ template "terracotta-server.fullname" . }} containers: - name: {{ .Chart.Name }} image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}" imagePullPolicy: {{ .Values.image.pullPolicy }} ports: - name: terracotta-port containerPort: 9410 protocol: TCP Demo : helm for fullstack app
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  KUBERNETES TOOLING :SKAFFOLD • Skaffold goal is to auto re deploy on save • Download the binary and you can start “skaffolding” • It’s not even necessary to provide k8s manifest files MAGICALLY AUTO REDEPLOY apiVersion: skaffold/v1alpha2 kind: Config build: artifacts: - imageName: gcr.io/k8s-skaffold/skaffold-no-manifest-example deploy: kubectl: manifests: Demo : skaffold for Java hello world
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  KUBERNETES BASED TOOLING: JENKINS X JENKINS, NEXUS, HELM AND FRIENDS IN THE CLOUD Very new !!!(public sinceMarch 2018) Available at https://jenkins-x.io/ Demo : JenkinsX on AWS
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  INTERACTING WITH KUBERNETESFROM JAVA HTTPS://GITHUB.COM/KUBERNETES-CLIENT/JAVA
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  SIMPLE JAVA WEBAPP TO LIST AND DELETE PODS THERE’S ALREADY A JAVA CLIENT API ! ApiClient client = Config.defaultClient(); Configuration.setDefaultApiClient(client); CoreV1Api api = new CoreV1Api(); //list the pods V1PodList list = api.listPodForAllNamespaces(null, null, null, null, null, null, null, null, null); pods = list.getItems(); //delete a pod V1DeleteOptions v1DeleteOptions = new V1DeleteOptions(); api.deleteNamespacedPod(name, "default", v1DeleteOptions, null, null, false, null); Demo : simple webapp to list and delete pods
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  © 2017 SoftwareAG. All rights reserved. For internal use only!22